he said nicole has gone missing. we are frantic. calling, all her friends are calling. you think that that sort of thing happens to other people. it's the most frightening thing in the world. >> a young wife. >> she always saw the good in people. >> she had a way to make you smile. >> missing for nine days. >> it's so wrong, and nicole is somewhere where she shouldn't be. >> it was hard enough when they didn't know. much worse when they did. >> it came over the tv that a body had been found. i'll never forget that, as long as i live. >> one mystery solved. another just beginning. what had happened to nicole? >> this could go down any number of paths. >> and it did. >> had her troubled past finally caught up with her?

>> i saw the pill bottle and i freaked out. >> or was it something much darker? >> he told me that he would put it in her red bull. >> how did she change? >> she became more sexual with people. >> who wanted her dead? >> he thought he was somewhat of a player. >> did it make him a kler? >> i'm lester holt, and this is "dateline." here is dennis murphy with "secrets in seattle." >> seattle was raw after a week of relentless winter rain. a woman lost had been found in the tangle of the blackberries. a naked body. a small tattoo on the back. a necklace and signs of strangulation. the detectives sent to a patch of trees and boggy undergrowth near the seattle airport's runways guessed it was her. they would soon be proved correct.

nine days to find her, the answer to where. another seven years still ahead to answer the questions of all homicides, who, and why. but we have to go back, before the crime scene photos and the medical examiners' findings, before she became those chilly words, "the victim." to find the dearly loved person named nici. nici pietz, wife and daughter, sister and friend. >> she seemed to be able to uplift people in ways that none of us knew how to do. >> she had a way to make you smile. she had a way to let you know that everything was going to be okay. >> gayle was her mother. >> nici was sunshine. she was the kind of person that when she walked in a room, the room lit up. >> gayle raised nici and her

sister, tanya, in the suburbs of seattle. there were carefree days at the nearby lake. >> is nici your annoying kid sister or was she a pretty cool kid? >> she was a very annoying kid sister. mom insisted on dressing us alike. >> in high school, mia says nici was a friend to everyone. >> every day, eating lunch together. she never sat. she would walk around and visit with people. she always saw the good in people. she didn't see the bad in people. >> after graduation, nici brought that winning spirit into the workplace. eventually landing a plum position in the head offices of bally total fitness. kimberly thomas was on her team. >> nici was a great boss. she cared about how your day was, she cared about how you were feeling. she cared about your birthday. >> bally's is where nici met david pietz. he exuded smooth confidence.

he seemed to be going places. >> he was definitely a very nice man. easy to talk to, would laugh a lot. he was actually a very compassionate person. >> he was very confident. he spoke well. he had a presence that demanded attention. >> dave was set on selling more gym memberships than anyone else. and he wouldn't have denied what everyone saw in him. he was ambitious, with his eyes on bigger management prizes. >> dave could sell reading glasses to a blind person. it didn't matter what his pitch was. he had you convinced that whatever it was, you had to have it. >> so there was dave, hustling on the sales floor, and there was nici, the buttoned-up blonde from corporate. and the boss' favorite hire was acknowledged. before long, nici and dave became an item. >> she definitely would get a little bounce in her step when she got an incoming message from dave. >> out of everybody, he chose

her. that has to make you feel kind of special. >> pretty soon, nici and dave moved in together. gayle had remarried and moved to arizona with her new husband, ron. and she could tell by the sound of her daughter's voice on the phone that nici had found the one. >> he was her dream man. >> really? >> he was the man she wanted. she was so in love with him. >> and he apparently with her. evidence to her friends and family, by the piece of jewelry she was rarely seen without. >> david got her a little tennis bracelet. >> diamonds on it? >> yeah, little tiny diamonds and white gold, i think. >> did she like it? was it a sentimental piece for her? >> she loved it. she wore it everywhere. >> another piece of jewelry from him would follow. a wedding ring. after dating for two years, nici and dave married. >> so tell me about the wedding. hawaii was the place. >> it was in hawaii. she looked so beautiful and happy. they both had leis and beautiful flowers in her hair.

and it was on the beach, with the waves crashing. and sunset. it was beautiful. it was absolutely beautiful. >> and was your sister happy on that day? >> yes. i think she found her prince charming. >> nicole pietz seemed to be on top of the world, and stepping confidently into her grown-up life. >> she was pretty excited about getting married. she loved her ring. she loved her bracelet that he got her. she was excited about getting a new condo. and having her own little family. >> january 28th, 2006 was a saturday. after a hectic work week at their different jobs, nici and dave would chill with a dinner party that night over at their friends' place. that afternoon, dave called nici to hash out the details. they would drive there separately. >> hey, babe, give me a call. i need to know what we're doing, if i need to stop and get food or anything for allen and jason and stuff like that. so give me a call. bye.

>> but when dave pietz showed up at their friends' apartment that evening, nici wasn't there. one hour, two hours, and still no nici. dave's wife of almost four years was gone, into the night. into the rain. what on earth had happened to nici pietz? >> nici's life hadn't always been so good. she had a troubled past. had those troubles finally caught up with her? or was it something else? >> did you think something was wrong, something more was wrong right from the beginning? >> yes.

nicole pietz, a woman just shy of her 33rd birthday, reported missing by her husband. >> we just want to know she's safe. >> david pietz told reporters how he waited for her with friends at a saturday night dinner party. she was a no-show. >> when i got there, she was not there, and hadn't heard from her and hadn't been able to contact her. >> david appealed for people to keep an eye out for her. >> we want her to know we love her very much. >> she is not somebody that doesn't come home. if she is ten minutes late, she calls you. >> did you think something was wrong right from the beginning? >> yes. because nici wouldn't have gone away without calling and telling me. >> if nici could have called somebody, she would have called gayle. >> nicole's mother and stepfather had reason to be worried. they, along with nici's other family and friends, remembered another time years before when they had almost lost her. nici had been in her teens when she began suffering from abdominal problems, related to

the onset of puberty. her medical issues left her in agonizing pain and also heavily medicated. >> she had very painful cramps and was prescribed lots of medicine for them. >> and by the time she was 21, she had had three surgeries. pain pills being thrown at her, right and left. >> at some point, it seemed all those pills took away not only the pain, but the person. zombified. how was she different? >> just spacey, couldn't keep up with the conversation. i felt like i lost her. she wasn't really there. >> before nici could crawl out of her hole, she would need to check into a local rehab center to treat her addiction. >> when she finally got clean, i felt like i had my sister back. >> that's when she started working at the bally gym office. her co-workers thought she was in terrific emotional shape. >> the nici that i know wasn't in her dark days. the nici that i knew was on top

of her game. >> and yet friends like michelle baltz knew nici took her sobriety a day at a time and was terrified of making one slip and losing it all. >> she would tell you she had a headache and trying to get the girl to take an advil. you would think you were trying to inject her with heroin. >> nici's weekly alcoholics anonymous meetings were the rock and foundation of that daily conscious effort. and on saturday morning, january 28th, she was supposed to attend a very special meeting. a celebration to honor her for eight years of sobriety. >> every year, it's your birthday. and it was her eighth birthday. >> as being a clean and sober woman. >> yes. she was so proud of it. we were so proud of her. everyone was proud of her. >> honey, it's mom. i don't know where you are, darling. >> but nici never showed up to that important meeting. never received her award. and now, friends and family desperately tried reaching her by phone.

>> hi, nici. this is rod calling. we don't know what's going on. >> their pleas relegated to the silence of voicemail. the anxiety level went off the chart. >> no matter what happened, nici, even if it was a relapse, we want you to know that we love you. >> had nici, in fact, fallen back into addiction? >> i started hoping that. because then she would have been alive. >> the alternative that nici may be dead somewhere was too much to bear. a bulletin went out. be on the lookout for a 5'3" woman with a tattoo on her back. friends knew she would likely be wearing a cross necklace and a diamond tennis bracelet. nine days later, king county detective, kathleen decker, was dispatched to an area near sea-tac airport, south of the city. >> the call came in from my sergeant, requesting i respond to this location regarding a woman's body. she had been found by a passerby

in the blackberry bushes. >> this is kind of off the grid right here. >> yes, it is. >> a woman's body discovered in a nothing patch of scrub at the end of the runway near an all but abandoned trailer park. >> what did you notice about the body? >> first thing i noticed was she was nude. the second thing i noticed, her arms were gently across her chest. >> not just a body abandoned. >> correct. she had not been discarded like garbage, but had been placed into and under the vines. >> the detective had a special set of skills she called on now. she had been trained in tracking, reading trails, disturbed vegetation, just like the scouts in the old west. the pattern of broken branches and tamped-down leaves and soil told her that the body had lain out here about a week. >> is there anything that suggested to you why this woman would have been abandoned here? >> no. and that was part of the complexity of this investigation. we had all sorts of avenues that we needed to investigate.

we had the transient population that may have been frequenting the trailer park. we had a mental health facility that was very close by, within walking distance. >> but detective decker did have a strong hunch about who this victim was. the cross necklace, the tattoo. all checked out as that local woman, nicole pietz, who had been missing for a week. the diamond tennis bracelet she always wore was not on her wrist, but police were confident enough in their tentative i.d. to pay a visit to nicole's husband, david. and the information david pietz would soon share with detectives about when his wife was last seen and what she left behind would be critical to the case. >> but it was something that was missing that turned out to be even more important, and puzzling. >> there's no indication that anyone else had been behind the wheel of nicole's car. >> when "dateline" continues.

with a great many bad days, one of the worst ones had to be the day she was found.

>> oh. i'll never forget that as long as i live. >> found strangled. >> it came over the tv that a body had been found and we just knew that it had to be her. >> had to be your nici. >> yeah. >> nicole pietz, strangled to death. her nude body left for a week beneath some blackberry bushes by the airport. the killer unknown. her gray jetta still missing. her family's deep sorrow, now hardened into resolve to get justice for her. >> find out who did it, and punish him. punish him. >> to begin, the lead detective now assigned to king county's newest murder case, jesse anderson, set out to learn more about the victim. he paid a visit to her husband, david pietz, at the condo he and nici shared. >> how long have you been married? >> almost four years. >> david agreed to be audio taped and told detectives that nici had struggled with chemical dependency in the past. he then revealed something

disturbing. recently, nici had again started taking prescription pills. >> is nici still struggling? >> she wasn't. but she hurt her back right before thanksgiving. she split the disk. >> because of a severe painful back injury, david explained, nici had reluctantly agreed to let her doctor put her on a carefully monitored prescription for percocet, a potentially addictive narcotic drug. >> at first, she had me keeping the pills and giving them to her. >> investigators wondered, had nici's old demons pulled her down again? they delved into nici's last known movements. >> when is the last time you saw nici? >> friday night when i got home from work. she was asleep in bed. >> david pietz told detectives that nici was sleeping when he arrived home late friday night. and by the morning, she was already gone. off to her special aa celebration, he assumed.

>> i just remember thinking that must be where she must be when i woke up. >> when she didn't show up at the dinner party that night, he returned to their condo to look for her. he described how her purse, car keys and gray jetta were gone. but he said something else caught his eye and it would turn out to be a big clue for detectives. nici's vial of percocet was sitting out on the counter. the bottle was empty. the 56-pill prescription filled just two days before, gone. >> i found the pill bottle and i freaked out. it was a little scary to think she relapsed. that's a lot of pills. i thought maybe she od'ed or something. >> as detectives wrapped up the interview with the husband, a narrative was starting to come together about the victim, of a former addict, possibly re-addicted. >> how does that change the complexity of the investigation early on? the woman whose body has been found was a recovering addict and maybe fell off the wagon? >> well, it makes it far more complex for us, because now we have to consider the possibility

that she met up with the wrong person at the wrong time, and that somehow led to her demise. that this was somehow related to the people that she knew through her aa affiliation. which she was very much into, and regularly attended those meetings. >> so doors are opening a possibility. >> yes. >> rather than closing. >> yes, yes. >> some old fashioned gumshoe investigative work would have to come next. tracking down phone records, credit card statements. anything to pinpoint where nici may have headed after leaving the condo saturday morning. only one more blip on nici's timeline surfaced. a single phone call made around noon on saturday from her cell phone to the gym's front desk while david pietz was working. >> it's possible that she was driving, and hit one of the towers there, so we were considering that. we were also considering whoever killed her may have had her phone and was still using it. >> as for that diamond tennis bracelet missing from nicole's wrist when they found her body, the cops began checking pawn

shop records, in case someone had tried to hock it. nothing. >> a police officer spotted pietz's car overnight. >> the last major piece of the puzzle turned up two weeks after nici disappeared. her car, a gray jetta, had been found abandoned in a parking lot in seattle's university district. forensic technicians hungry for clues crawled through the car. they noticed the driver's seat had been pushed back, but it's what they didn't find inside it that intrigued investigators most. >> what was found in the car was david's dna, along with nicole's dna. there is no indication that anyone else had been behind the wheel of nicole's car. >> detectives were now wondering. wondering about the husband. >> coming up. he was definitely a player. >> dave chased women inside the club, outside the club, on side of the club, on top of the club. >> but did that make him a killer?

at the latest gym where david pietz worked, co-workers like troy wagman understand full well why david looked so rough. still, it was a hard thing to witness. >> he looked very bad. he looked like he hadn't slept, lost weight, dark circles under his eyes and he seemed a little bit more sad.

>> while david pietz slowly got back to work after taking time off to mourn his lost wife, detectives intent on solving her murder began interviewing people from the gym world who knew the couple. starting at the facility where nici and dave had first met. >> bally's was the type of place were most of the rumors weren't really rumors. they were true. >> staff members agreed that dave, the alpha dog of the sales department, and nici, the nice girl, were a hopeless mismatch. >> the more nici liked him, the more i knew she shouldn't. >> what dave saw in nici, according to some co-workers, was a cynical way to climb the corporate ladder. nici was everyone's favorite, and their boss in particular loved her like family, as c.j. brady saw it. >> nici and our supervisor were very close. almost like a father/daughter relationship. and that is why i think he dated nici, from the start. i don't think there ever was an attraction there. >> but if he was chilly about

his wife, he was super-heated about some of the female gym members and his co-workers. >> dave chased women inside the club, outside the club, onside the club, on top of the club. >> detectives found the tales about david pietz's roving eye intriguing, but hardly damning. >> i guess to describe it in current terminology, he thought he was somewhat of a player. >> did it make him a killer? >> didn't make him a killer, no. >> but david pietz's behavior towards women at the gym did get him fired, detectives learned. several female co-workers filed sexual harassment complaints against him with bally's management, including jackie morales. >> david was very verbal when it came to his comments. what looks better on jackie today, her legs, her butt, or breasts. i finally got the courage to go to the boss. >> after getting booted from bally's, david moved on to a job at 24-hour fitness, where troy wagman remembers david talking about how he and his wife nici wanted to invite others into

their sex life. >> more than once, he would approach me and ask me what i thought about three-ways in a relationship. and he and nici were exploring the idea of swingers' clubs. >> nici's good friends knew it differently. >> she was very appalled at that idea. >> she was like, absolutely not. >> a wobbly marriage, a hound dog husband, straining at the leash. the circumstantial smoke was getting thicker for investigators. >> it was very apparent to me that, you know, he was leading an alternate lifestyle. >> what i'm not hearing, captain, is motivation. >> that was a concern for all of us, too. >> maybe the husband did it. but then again, maybe he didn't. as weeks became months, the solid proof, the hard evidence that the investigation needed, just didn't fall into place. an investigation hitting a brick wall. devastating news for nici's family, by now convinced of david's guilt. >> when you were out in the emotional wilderness, gayle,

'07, '08, '09, what was your lowest moment? >> oh, there were so many low ones. i didn't want to live. just cried my head off every day, and -- just didn't want to live. >> nici's mother marked the passage of time by making public pleas to find the killer. >> it has been 839 days since my beloved nicole was murdered. >> years went by. david pietz quietly left the fitness industry for a position at chase bank. he started attending church. fellow church member, kim adams, says she got to know a dave who was very different from the heartless philanderer described by nici's friends and family. the dave kim knew was a forlorn widower who spoke fondly about his lost wife. >> when he would speak of her, i could see a sadness in him. we would have conversations about, you know, he was struggling, because he missed

her. >> meanwhile, at the county sheriff's office, the three-ring binders that made up the pietz file moved from desk to desk, until in 2010, they were picked up by two cold case cops, jake and mike mellis. each was determined to apply some heat. >> i called gayle up and said i've got this case now and it's my intent to be the last detective to have this case. >> they laid out the entire investigation, and then homed in on day one. that saturday morning nici pietz presumably left the condo she shared with dave and headed out to her special aa meeting. to the cold case detectives' fresh eyes, a few key pieces of evidence from that morning jumped out. common-sense stuff, really. like nici's wedding ring. a photo taken in 2006 showed it in nici's bathroom near the jewelry cleaner she kept it in overnight. >> and here's the wedding rings left on the counter. and she was proud of the rings, according to all of the family, and here she is going to this

big meeting the next morning, but she is going to go and not take her rings with her? >> another red flag, this from the autopsy report. nici's body had been recovered with her retainer still in her mouth. why did it seem odd you found the body with the retainer? >> again, that's something people typically wear when they go to bed. she was in the habit of wearing it at night, but no place else. >> the wedding ring left on the bathroom counter. the clunky retainer still in her mouth, added up, concluded the detectives, and you had a wife who never left the condo for that meeting saturday morning. one who never made it through the night alive, and the only person known to be with nicole pietz in the condo that night, her husband, david pietz. >> when you look at each piece of evidence and figure out how does it relate to everything else, lo and behold, we've got our picture at the end. >> six years after nicole pietz was reported missing, her husband david was arrested and charged with second degree murder in connection with her death.

coming up, a lifestyle on trial. >> who did it involve? >> me and katie and dave. he was just trying to loosen her up to get her to do a threesome. >> when "dateline" continues. at shell, we believe the world needs a broader mix of energies, which is why we are supplying natural gas, to generate cleaner electricity, that has around 50% fewer co2 emissions than coal. and why with our partner in brazil, we are producing a biofuel made from renewable sugarcane to fuel cars. let's broaden the world's energy mix, let's go.

36% of all teachers in the u.s. have been teaching for more than 20 years. what does that mean? do the math. we need more teachers to lead future generations. the more you know.

it had been seven and a half excruciating years of waiting. last september, nici's family and friends filed into a packed seattle courtroom to watch david pietz stand trial for his wife's murder. he pleaded not guilty. >> when nicole married the defendant, she thought she had married the man of her dreams. but on january 28th, 2006, that dream would turn into a nightmare. >> prosecutors kristen richardson and carla carlstrom, promised the jury pieces of a puzzle. pieces they hoped would ultimately reveal a resentful, hateful husband, whose frustrations had boiled over. >> i think it was actually, i hate this phrase, but it truly was a crime of passion. >> at the core of the prosecutors' case, david was a sexist philanderer who viewed his goody-two-shoes wife as a weight around his neck. so he put his hands around hers

after an argument to free himself of the burden. david they said then turned to nici's problem with pills as his cover-up. >> why kill her? >> it wasn't a plan to murder. if it was something he planned to do, sure, he could divorce her. this was not a plan. this was something that erupted one night in a fit of rage. >> because they thought there was no premeditation, david pietz was charged with second, not first-degree murder. but proving he snapped and strangled nici in their condo wouldn't be easy. this was a highly circumstantial case with little direct evidence pointing david's way. >> in terms of the bedroom or the house, there is no physical evidence left behind. >> which is a handicap for you guys, when you've got to tell this story to a jury that really wants to hear csi, right? >> they want dna on everything. >> prosecutors started by calling a string of the other women in david's life. women who shared with the jury stories of a lustful, cheating spouse, with little regard for his wife. stories of a three-way kiss at the bar. >> and who did it involve?

>> me and katie and dave. >> you were kissing katie. >> uh-huh. >> katie was kissing you. >> yes? >> all three at the same time. >> stories of a one-night stand. >> and what happened at your place? >> we had sex. >> and is that the only time that had happened? >> yes. >> and of a romance that started while david and nici were engaged. >> i asked him why he was getting married, and he said that at that point it was too late to back out of it. >> the romance lasted on and off for two years. >> what did he tell you about how he felt about you? >> he told me he cared about me. >> dave pietz's lifestyle became the trial here. >> it did. because it showed he was dissatisfied with her. >> dissatisfied with nici, and prosecutors say, determined to change her. david went so far as to spike nici's drink with a club drug, ecstasy, hoping she would finally agree to that threesome.

this, according to david's bar buddy, renee stuart. >> he told me he would put it in her red bull when he went to get a drink, and he was just trying to loosen her up to get her to do a threesome. >> did you notice a change in her after she drank that red bull? >> yes. >> how did she change? >> she became more sexual with people. >> here's a guy who knows full well his wife has addiction problems and he puts ecstasy in her red bull? is that the way this goes? >> right. she fought so hard for sobriety, and without even knowing it, her husband was undermining that. >> and then it was nici's sister tanya's turn to stare david in the eyes and tell jurors how indifferent he appeared immediately following her disappearance. >> did he ever look for her? >> no. >> did he ever make any phone calls related to her disappearance? >> no. >> did you ever see him join in searches with people from aa or her workplace? >> not at all.

>> but prosecutors feared evidence of suspicious behavior from a reprehensible husband wouldn't be enough to convince a jury david committed murder. so they rolled out their theory that nici never left her condo alive. >> honestly, the best evidence we had was the evidence that showed she never left that condominium. >> evidence offered of david's little mistakes. remember nici's cherished wedding ring, left on the bathroom counter. and then there was nici's retainer. >> he forgot she wears a retainer/night guard. and he forgot to check her mouth before he dumped her. >> something else nici's killer would likely overlook, the food found in her stomach by the medical examiner. based on the m.e.'s analysis, prosecutors suspected nici was killed sometime between midnight and 2:00 a.m. that friday night, soon after david said he came home and said he found nici in bed. but it was what the forensic scientists didn't find in nici's

system that they found more damning. evidence they said that proved once and for all that nici had not relapsed. >> did the m.e. find evidence of prescription pain killers? >> no, she had less than one therapeutic dose of percocet in her system. it was clear she had not been using percocet probably for a few days prior to her death. >> and then there was nici's bracelet, that gift from david, the source of her joy. david had told police it had vanished, along with his wife. >> everybody assumed that, who knows, the killer took it. >> soon after david's arrest, police learned from co-workers that he had the bracelet all along. >> david said he had a bracelet that he had taken to a pawn shop, and he thought that the guy was trying to rip him off. >> he was trying to hock it, make a few bucks. >> trying to make money. >> and that spoke to his cover-up. his involvement. >> sure. absolutely. and that he had lied to police in the beginning and saying he didn't know where that bracelet was. >> still, one piece of the puzzle didn't fit the prosecution's theory, that saturday phone call made from

nici's cell phone to the 24-hour fitness gym where david worked. >> this is evidence that at around noon, she is alive on saturday. >> right. >> using telephone company records, prosecutors argue the origin of the call could be placed within a few blocks of the gym. >> what you're saying is there is a 90% to 95% probability that the phone was in this reddish/orangish sector when it was being placed. >> that is correct. >> it became very clear, that call was placed from the 24-hour fitness gym when david pietz was working there. >> hardly conclusive evidence on its own. but detectives found something else on the gym security video that made that call a jaw-dropper. at just about the same time the call is made from nici's cell phone, david can be seen stepping away from his work area, out of the camera sight. that was david, prosecutors say, heading off to use nici's phone to call the gym receptionist. >> he went back and placed that call and then came back out front as if nothing was happening.

he had to convince the police she had left the house that morning. because if she hadn't left the house, he was the killer. >> that video and that cell phone call were presented as the final pieces of the prosecution's now-completed puzzle. >> we had needed just one more thing to put us over the top. just one more thing. and that call, that put it over. >> but the jury had yet to hear from the defense. which wasn't about to let such a circumstantial argument go unanswered. coming up. who really had something to hide? was it the accused killer? or nici? who certainly had a lot of pills around. >> on january 12th, she got 56. on january 18th, she got 56 and on january 26th, she got 56.

rows of nicole pietz's family and friends listened to the prosecution describe the accused as an oversexed, run-around louse of a husband. a guy who left her to rot in a scrubby bog. >> we know how she died.

we know how he lied. >> each day, david pietz remained emotionless in court. and, trial-watchers noted, alone. and few if any family or friends showed up in the rows behind him to have his back. but he did have supporters, like kim adams, a friend from church. >> he does have a very strong network of friends and people who care about him and love him. >> she says team dave chose to back him quietly from outside the courthouse, hoping to avoid the many cameras both in and outside the courtroom. >> i have a lot of respect for those people that didn't go. he knows who loves him. >> she watched the news in disbelief, not recognizing the man prosecutors descbed as a cold-hearted killer. surely, this wasn't the dave she had known for almost seven years. her trusted confidante. >> i kept thinking about myself, they're talking about my friend, but that's not my friend. that's not the friend that i know. >> but in court, his defense team would not call on kim and the silent friends as character witnesses.

the defense was mounting a stripped down argument. jurors, there's nothing here. nici left the condo that morning, and dave had no idea where she ended up. >> nicole pietz was missing. and her husband, david pietz, never saw her again. what happened to nicole is a mystery. >> after ten days of trial, with more than 40 witnesses, the state, the defense lawyers argued, had failed to produce a smoking gun or even a plausible motivation for murder. >> in this case, there are many reasonable doubts. >> could anyone say with absolute certainty that she always wore her wedding ring? that she never went out in public with her retainer? the picture of the defense portrayed was of a david pietz open and honest with detectives right from the start. a husband hoping the police would locate his wife. detective kathleen decker took the stand. >> when you first saw david at

his residence, i believe you described him as very anxious and upset. >> yes. >> the defense willingly conceded that david pietz was a crummy husband. but skirt-chasing didn't give him a motive for murder. >> dave pietz isn't the first guy to step out on his spouse. all of you, certainly, know of people that have done that. have they killed their wives or husbands or anything like that? >> and, the defense countered, that if anyone had secrets to hide, it wasn't dave. it was nici. >> there's another side to all this. >> the defense now turned the focus to nicole pietz, and the last few weeks of her life. >> raise your right hand. >> the lawyers called to the stand their main witness, nici's doctor, carol waymac, nici's primary physician for five years. >> you knew nici's history, that she had trouble has a young woman. >> i did. >> and had actually been in rehab at one point. >> and we had talked about it throughout her care with me.

>> so when nici came into the office complaining of severe back pain at the end of 2005, doctor waymac said she had nici's past addiction in mind. the doctor testified that she did put nici on pain medication. but said she tightly monitored nici's weekly prescription, right down to counting the number of pills. >> on january 12th, she got 56. on january 18th, she got 56. and on january 26th, she got 56. >> nici was getting hundreds of pills, but the defense reminded the jurors that nici's toxicology report had shown something unusual. despite being prescribed all those pills, the forensic scientists said she apparently hadn't been taking many of them. >> is it your opinion that this just reflects like a one-time use? >> i believe so. it's such a small amount. >> almost no drugs in her system meant something was very fishy, said the defense. >> nicole was lying to her doctor.

>> she was doing something with those drugs other than taking them. >> so what was she doing with them? >> inferentially, circumstantially, you could find she was out giving these drugs away, giving them away to old friends of hers, coming into contact with drug users and dealers, pretty tough people, pretty dangerous. >> the lurid story may never be known, argued the defense. they said it was clear that nici and not dave had something to hide. >> something went terribly, terribly wrong, and she died as a result. that it wasn't david, but it was somebody else. >> now it would be up to a jury to decide. a husband who never loved his wife, who lost it on one very bad night. or a woman with an addiction she never beat, and some final hour, doling out narcotic pain killers to the wrong person. at the courthouse, the jury retired to deliberate. kim adams waited at home for news.

>> kind of made a promise to myself to support him, no matter what the verdict was. because i feel he would do the same for me. >> as the hours went by, nici's family prayed. and the prosecutors replayed the case in their heads. >> i felt like there was absolutely nothing we missed in closing or in presentation. >> but that's not to say when they're out deliberating you're not wondering every second what's going on, and whether you're going to succeed. >> please be seated, with the exception of the presiding juror. >> and then, more than seven and a half years since nici's body had been found, the jury was coming back with a verdict. >> we, the jury, find the defendant, martin david pietz, guilty of the crime of murder in the second degree, as charged. signed by the presiding juror. is this the verdict of the jury? >> yes, it is. >> david pietz, guilty of second degree murder for strangling nici, his wife of almost four years. >> oh. absolute elation.

i just wanted justice for my daughter. and we got it. >> what do you want to say to david pietz now? >> david, i hope -- i hope you find it in your heart to be sorry. because if you don't, you'll burn in hell forever. >> david pietz returned to court for his sentencing. presiding judge michael haden expressed disgust that david had strangled his wife, who trusted him. >> i don't know what was going through her head as she looked into the face of the man she thought she loved as he took her life away. accordingly, the sentence will be -- >> judge haden sentenced david pietz to 18 years in prison, the maximum time allowed in this second degree murder case. before her daughter's convicted killer was led away, nicole's mother had this to say. >> i've let david take my life for the last seven and a half years. but i'm not going to anymore. david, i forgive you. i'm not going to allow myself to

let you rule my life anymore. >> but gayle says she would still like to ask her former son-in-law a final question. >> i wish david would tell me why. and how could he ever harm such a nice person. i mean, nici was -- was such a good person. >> the hardest question, always the why. the coldest fact, the young woman gone too soon. >> that's all for this edition of "dateline." a memorial in santa barbara after the mass killing last night. and new information on the 22-year-old man who police say was behind the violence. san francisco getting ready for a warmup.

i don't care where you live, it's going to happen to you. >> the three male victims were apparently stabbed repeatedly with sharp objects. and it was -- it was a pretty horrific crime scene. >> friends, family and strangers gather tonight to remember the victims after that mass killing near uc santa barbara. and now there are questions about whether authorities missed an opportunity three